The "dynamic state" hypothesis of viral persistence permits us to postulate that, depending on fluctuations of and interaction between the humoral response and virus replication, a herpetic recurrence may either be elicited or aborted. To test this, a long-term experiment will be instituted in ocularly infected rabbits. The serum antibody and virus replication in the eyes will be measured at close intervals and clinical recurrences recorded. It is hypothesized that a recurrence may coincide with a transient decrease of the immune response, followed by an increase of virus replication. As recurrences are believed to be induced by systemically applied epinephrine, it can be envisioned that epinephrine, via increased released of ACTH, may elevate serum cortisone levels and, thereby, suppress the immune response. Passively administered antibody significantly ameliorates the herpetic eye disease. Therefore, homologous immune serum will be injected at time intervals into infected rabbits to see whether a sustained high level of antibody may reduce the frequency and/or severity of recurrences. Experiments completed during the first year of this project have shown that rabbit immune serum injected early during the acute state and periodically during the chronic phase significantly reduced the incidence and duration of clinical recurrences. Paradoxically, the immune serum treated rabbits had a significantly higher rate of viral recurrences. To validate these results, the experiments will be repeated and a new control group introduced: rabbits treated with normal rabbit serum. In our earlier experiments, normal rabbit serum had no effect upon the severity of the primary acute disease. It remains to be seen how it will affect the chronic recurrent phase.